"All parts should go together without forcing. Remember the parts you are reassembling were disassembled by you. If you can’t get them together again, there must be a reason. Do not use a hammer." ~ IBM

When I designed our audio amp, I struggled with noise. The original amp used a digital signal and the amplifier was muted during silence. There was virtually no noise. The problem with using the P.C. power supply is that it brings the noise right into your circuit. There are differences in the grounds which cause problems similar to ground loops. Your solution appears to use ferrites, but there is an active solution as well. Check out the BA3121 ground isolation chip. I was headed down that path, but the cost and part count was getting ridiculous. Using the external power supply that we use, brings in clean isolated power so I don't have to try to filter the noise out.

Thanks for the info on the chip, sound interesting. I've been trying to install everything into an existing case (see my other post) so i can plug it into any stock rfm to instantly upgrade it. I wish i could fit 2 psus in there, or find a better small form factor psu with isolated grounds or something. I was pretty sceptical about this ferrite ring type solution, but seems to work pretty well.

"All parts should go together without forcing. Remember the parts you are reassembling were disassembled by you. If you can’t get them together again, there must be a reason. Do not use a hammer." ~ IBM

Menace wrote:I've ordered a ground loop iso as well in hopes that I can get away with a single PSU as well. I'll post my results once it arrives.

Doug

Just thought I'd report back with an update. Received the ground loop iso that I bought off Ebay for $1 (Plus $8 shipping), installed it last night and I now have nice clean sound from the OEM amp running off the mobo power supply.